1 Field of the Invention
The present invention relates to apparatus and methods for preventing birds from perching on structures so as to keep their droppings from accumulating on objects directly below. More particularly, the apparatus is especially suited for placement on billboards and their related support structures to prevent bird droppings from accumulating the billboard flames and the signs posted below. The present invention also relates to apparatus and methods for preventing birds and small animals from crossing, nesting or chewing through elongated cylindrical structures such as utility lines or other cables over which one embodiment of the invention may be placed.
2 Prior Art
Within the billboard industry, great inconvenience and economic waste is created by birds perching on billboards and defecating upon the frames, structures and signs below. As bird droppings accumulate, they cause great difficulty for workmen who must maintain and replace the signs on the billboards. The accumulation presents a health hazard to the workmen who come in contact with it. The accumulation also facilitates deterioration of the signs in both visual appearance and structural integrity, thus creating the need to maintain and replace the signs more often.
Several solutions to this problem have been attempted with varying degrees of success. One of the oldest and most common methods of preventing birds from gathering and perching on top of an object is to place a molded figurine of an owl or a hawk in close proximity to the roosting area. The presence of an apparent predator in the area will naturally keep most birds away, at least temporarily. However, the drawback with this method is that the figurine's utility is lost once the birds realize it is only a harmless, stationary piece of plastic.
Another common method of preventing birds from perching on a surface is to apply an adhesive glue to the surface itself. The discomfort caused to the birds from having their feet stick to the surface is sufficient to persuade them not to perch on the surface again. Although this method has proven successful, bird droppings from initial roostings still accumulate upon the treated surface, causing the adhesive to quickly lose its effect. Thus, once a large number of birds have tried perching on the treated surface, the adhesive must be reapplied.
One of the more recent methods of preventing birds from perching on top of billboards has been the use of motorized wire propellers placed above the billboards. The wires rotate circularly in a generally horizontal plane similar to helicopter propellers so that the birds are unable to land or perch on the surface beneath the propellers. The main disadvantage of this method is that it requires electricity, which may not be available at billboards located along isolated highways. Another problem is the high cost to purchase, install and maintain these motorized wire propellers.
In addition to the above noted methods, several other, more simple solutions to the problem have also been attempted. One method of preventing birds from landing on a structure is to encapsulate the structure with a material which acts as a barrier, such as chicken wire or plywood. Another method commonly used is to place nail-like spikes having pointed ends into the landing surface so that the birds have no place to land but on the points of the spikes. Another method, which is not in favor at present, is the placement of arsenic-laced feed in the vicinity of the perching area. A further method which is simple and convenient to use is the placement of "mylar strands" around and upon the structure, so that the strands produce an annoying hum when the wind blows, scaring any birds away.